Turbine blade with an impingement cooling insert

A gas turbine, comprising:

• an inlet that admits a working fluid;
• a compressor section connected to the inlet that compresses the working fluid;
• a combustion section that receives the compressed working fluid and combusts a fuel to produce a hot working fluid;
• and
• a turbine section that expands the hot working fluid having a of hollow turbine blade, comprising:
• a blade root,
• a platform section arranged on the blade root,
• a hollow blade airfoil arranged on the platform section having an interior wall surface that defines an interior portion of the hollow blade airfoil, and
• a sheet metal-form impingement cooling insert arranged in the hollow blade airfoil that separates the interior cavity to form an interspace portion and a cooling medium passage, the interspace portion defined as a rectilinearly extending gap opening between the interior wall surface and the cooling insert where a cooling medium flows from the cooling medium passage into the interspace portion, the cooling insert comprises a plurality of cooling insert sections arranged one upon the other overlapping in an overlap area having a wave-like cross section and extending parallel to the rectilinear gap,
• wherein for sealing the overlap area the cooling insert sections are displaced in such a way that in the overlap area a contact surface is formed, the contact surface extends rectilinearly.